52 



them away by the aid o£ other agents. Moreover they have 

 proceeded on the assumption that the annual temperature at 

 any one place was affected during cosmical changes in propor- 

 tion to its distance from the advancing or retrograding wave 

 of glacial cold ; that the environments remained the same, 

 and therefore by rule of proportion the increment or decre- 

 ment of heat was invariable. Thus, then, the main grounds 

 of rejection of the evidences of glaciation may be briefly 

 stated as follows : — That the existence of glaciers is incom- 

 patible with the high temperature that must have prevailed 

 over this area during the glacial epoch of the southerm 

 hemisphere. 



If the east coast of the South Island of New Zealand were 

 known only, with what incredulity would have been received 

 the announcement that the transalpine glaciers reached to 

 within 700 feet of sea-level, or 2,000 feet lower than those on- 

 the east slope. Of course we understand the why and the 

 wherefore ; but had we formed preconceived notions touching 

 the climatology of the western region, based on eastern expe- 

 riences, how erroneous would they have proved. 



Existing causes tend to maintain a higher mean temperature 

 for southern Australia than is demanded by its latitudinal 

 position, and to these Dr. Lendenfeld appeals as fatal to the 

 existence of glaciers except on the alpine plateaux, even at the 

 period of extreme cold ; and Professor Hutton argues much 

 in the same way. But were these causes operating with the 

 same intensity always as now? I think not; and their 

 removal and the reciprocity of actions in consequence thereof 

 may have resulted in the production of a climate which, com- 

 pared with the present, may have offered as great a contrast as 

 those of the eastern and western slopes of the New Zealand 

 Alps. 



To state my case : — If we study the present distribution of 

 temperature and aqueous precipitation on this continent, we 

 shall recognise a central arid area from which all around the 

 rainfall increases — tropical rains to the north and winter rains 

 to the south of it. Here in this almost rainless region originate 

 those desiccating winds, which materially elevate the tempera- 

 ture of the southern shores. G-uyot has shown that the exist- 

 ence of a dry belt on either side of the tropics is due to per- 

 manent laws governing the motion of aerial currents. The 

 locus of high barometric pressure or descending equatorial air- 

 cohnnn has a seasonal motion within certain limits — being 

 dependent on the position of the sun in its annual path ; so 

 also will it be affected by changes in the obliquity of the 

 earth's orbit. The area of high pressure, or of aridity, has an 

 annual oscillation, and must have also a cvclical one. This 



